The flight tests will initially prove the Dream Chaser's aerodynamic qualities using an engineering article being outfitted at Sierra Nevada's space campus in Louisville, Colo.

Using a combination of public and private funding, Sierra Nevada is developing the Dream Chaser to carry up to seven astronauts to the International Space Station and back to Earth. NASA has promised the company $125 million so far, with the bulk of the money already awarded to Sierra Nevada upon completion of predetermined development milestones.

"Our mission is very specific: to take crew and cargo to the International Space Station and to low Earth orbit," said Mark Sirangelo, Sierra Nevada's executive vice president and chairman of its space systems division.

Sierra Nevada has provided the Dream Chaser program with "tens of millions" of dollars in internal funding, but less than NASA's total investment, according to Sirangelo.

The remaining NASA funds will be released after the Dream Chaser's preliminary design review, scheduled for late May, and captive and free flight tests over Colorado and California.

"We've made amazing progress without a lot of money," Sirangelo said.

The Dream Chaser is based on the HL-20 lifting body concept studied by NASA's Langley Research Center from the late 1980s to the early 1990s. Launching into orbit on top of a United Launch Alliance Atlas 5 rocket, the spaceship will dock with the International Space Station and can stay there for more than six months. At the end of its mission, the craft will enter the atmosphere and make a piloted touchdown at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida.